This disclosure relates to apparatus for penetrating wellbore obstructions. Such obstructions may be, for example, a collapsed wellbore section, a wellbore plug, a failed flapper in a downhole safety valve, and the like. The disclosure also relates to removing a section of wellbore conduit (“tubular”) or penetrating several nested wellbore tubulars to access the wellbore externally to or off such tubulars.
In the hydrocarbon exploitation industry, there is often a need for penetrating an obstruction in a wellbore, where such an obstruction may be a section of a collapsed wellbore and tubulars, a “fish” in the wellbore that cannot be removed by traditional wellbore milling tools, and the like. Such a “fish” may be a barrier installed, for example, in the form of a wireline plug, a failed flapper in a downhole safety valve, a lost tool string, a logging tool, and so forth. Penetrating such obstructions can be required to bring the well back to normal operation or to obtain access to the wellbore below the obstruction to plug and abandon the well.
It is common, with various rates of success, to remove or penetrate such wellbore obstructions using lightweight wellbore milling tools deployed by wireline or coiled tubing. In some instances, attempts may be made to remove or penetrate the obstruction with heavier intervention apparatus deployed on jointed pipe; however, such methods are without guaranteed success.
Hence, there is a need for methods and devices that can be used to mechanically mill away, or to disintegrate, an obstruction sufficiently for this obstruction to fall into the wellbore below an interval of interest or to be retrieved to the surface.